I have also opened the ports 5000-5100 and 3478-3479 UDP and TCP on my
router/firewall USRobotics 9108.
I have also sniffed the packets using wireshark and is clear that simply
nothing come back from the server.

I have also tried to deactivate the STUN support but obviously the
server has answered "606 not acceptable".

Maybe there is something wrong in the packets sent to the server (IP,
port or anything else)?

Thanks in advance,
Filippo
Damien Sandras ha scritto:

There is probably a firewall in-between dropping packets. Everything
looks normal.
You might try 3.00 which does not use non-standard ports like 2.0.12
did, it might help (or not).